1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine.
2. Description of Prior Art
In the past, a semicircular paper feed roll having a portion of a circumference cut away has been used as paper feed means. It is less expensive and more compact than a method in which papers are fed by moving up and down a rotating roll, but when a preceding paper jams during the paper feed operation, that is, while a roll surface is in contact with a paper and the machine is stopped, the roll is, in many cases, held in that position, and when the machine is restarted after the jam condition has been cleared the roll feeds out the paper by the return operation to a home position. As a result, in the above copy operation, a jam may occur or a misregistration of a copy image may occur. This problem is encountered in other paper feed means which use a rotating roll which is held in an interrupted condition when the machine operation is suspended.
Where another process movement member is held in the interrupted condition when the machine operation is suspended, the process is not started from a proper point when the machine operation is restarted and the first copy does not provide an acceptable copy.
If the machine operation is suspended by the detection of a jam immediately after the start of the paper feed operation, the machine stops with a leading edge of a paper slightly projecting from a paper cassette. In such a case, a trouble condition of the machine may not be detected by the observation of the machine through a machine door. If the machine is restarted from that condition, a jam may occur again or a misregistration may occur.